jobs has a different return code if used in a pipeline

[Lucretiel]

While trying to write a simple wait command, I discovered that jobs behaves differently in a redirection or pipeline:

$ sleep 10 &
$ sleep 10 &
$ jobs
Job     Group   CPU     State   Command
2       ...     0%      running sleep 10 &
1       ...     0%      running sleep 10 &
$ jobs | cat
2       ...     0%      running sleep 10 &
1       ...     0%      running sleep 10 &

This makes perfect sense to me- many shell utilities have this behavior. However, jobs ALSO changes the return code if it is used in a pipeline:

$jobs; echo $status
jobs: There are no jobs
1
$ jobs > /dev/null; echo $status
0

This means that the following simple wait implementation doesn't work:

function wait
    while jobs > /dev/null
        sleep 0.1
    end
end

jobs should be changed to behave like count, set -q, etc. to return an error code if 0 jobs were found.

[maxnordlund]

I've encountered the same issue, but I'm not sure if it should return 0 when jobs are found. It makes more sense how it is now with it returning 0 if there are jobs to report on, e.g. jobs --pid.

[maxnordlund]

This should be resolved by the above commits, close this?

[ridiculousfish]

Thanks!